Development history of the VTOL aircraft

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FRS.Mk 1 Sea Harrier of the Royal Navy

This article covers the evolutionary history of the VTOL aircraft . The high point in the development of vertical take-off and landing aircraft was in the 1950s and 1960s. After a subsequent stagnation, the attempt was made again with the F-35B to use this technology in a military mission aircraft. The Bell Boeing V-22 currently in use (2016) can be seen as a successful implementation of the convertible aircraft concept , which is also part of the VTOL aircraft . The currently only civil vertical take-off project is the AgustaWestland AW609, which is derived from the V-22 and has been in development since the mid-1990s .

Prehistory of vertical flight

The first mention of the technique of changing the thrust vector of an engine, which is crucial for VTOL aircraft, can be found in a 1909 letter from C. Edgar Simpson. He advocated that the aircraft engine should drive a fan and that the air flow should be directed through rotatable ducts so that either propulsion or vertical lift could be generated. In 1910, James Robertson Porter applied for a patent for thrust vector control in air and seagoing vessels. The motors were supposed to drive centrifugal compressors , the exhaust air of which was to be directed through rotatable bent pipes on both sides, thus generating recoil in any desired direction.

First concepts

The first serious design approaches for vertical take-off aircraft came in Germany in the early and mid-1940s. Apart from an unsuccessful vertical take-off attempt with the Bachem Ba 349 rocket aircraft in March 1945, the first design that could in principle be considered feasible was the Focke-Achgelis Fa 269 from 1941. Dornier then used a similar drive system in the 1950s at the Thu 29 . A third design from the time of the Second World War was the Focke-Wulf drive wing .

After the Second World War, parallel to the development of powerful turboprop engines, a systematic development began, first in the USA. The US Navy searched the VTOL " Quarterdeck -Jäger", which should be able to operate in a minimum tonnage in order to protect without the use of aircraft carriers convoys, while the US Army hosted their research towards the flying Infantryman to take part in combat on his own flying platform.

However, it was not possible to convert a VTOL aircraft into a production-ready version until the end of the 1940s.

1950s

At the beginning of the 1950s, a large number of concepts were designed especially in the USA, most of which were also implemented in prototypes. The US Navy and Ryan made their first attempts at the end of 1950 with a vertically arranged J33 engine that was equipped with remote-controlled control surfaces in the nozzle. You could get on and off this “flying machine” and let it float back and forth within small limits. This prototype first flew on October 20, 1950, powered by an Allison J33 jet engine. After further hovering flights, a cockpit was assembled, which consisted of the fuel tank of a Boeing B-47. On November 24, 1953, the first manned hover flight of a jet-powered aircraft took place with test pilot Peter Girard. With this device Ryan was able to gain important experience for the construction of the X-13.

The turboprop-powered Convair XFY-1 , developed on behalf of the Navy and flown for the first time in November 1954, is considered to be the first actually flown and controllable VTOL aircraft in the strict sense . With the XFY, a transition from hover to level flight could also be carried out for the first time. However, since the handling of the aircraft operating as a tail starter (tail-sitter) turned out to be too difficult for operational pilots, further development was discontinued. The first transition of a convertible aircraft was carried out by a Bell XV-3 in December 1958 ; here, too, further development had to be discontinued because the large number of technical problems could not be solved. Bell was also one of the pioneers in the development of a whiz with the prototype Bell ATV with two small J44 jet engines, which was mainly composed of Cessna parts .

While the already well developed turboprop engine was preferred in the USA during these years, the development in Europe was more oriented towards the use of jet engines. In Great Britain, Rolls-Royce developed the Thrust Measuring Rig (TMR), which in August 1954 carried out the first vertical take-off of a jet-powered aircraft from a horizontal position with the test pilot RT Shepherd. This can be seen as the beginning of the technical development that is today associated with the term “whiz kid” in public.

A short time later, SNECMA in France designed the Atar Valance, the first ring-wing aircraft . This rear starter was remotely controllable and consisted of an Atar engine installed in a tubular fairing. This then resulted in the SNECMA C.450 Coléoptère with an attached pilot's cockpit. Hawker built the P.1127 , which later led to the Harrier . Many designs for convertible aircraft from the early 1950s, such as B. the stop rotor design of the Sikorsky XV-2 did not get beyond the project stage.

In the civil sector, there were extensive plans to set up feeder services for city centers with VTOL aircraft. Batteries with 10, 20 or even more lift engines should ensure take-off and landing capability. Messerschmitt Me 408 and Hawker Siddeley HS. 141 are an example of this. Transport flights “at jet speed directly from the city center” should become a reality. However, these plans failed both due to the noise problem and economic reasons, because the lift engines were too much additional ballast. In addition, safety reserves had to be planned in the event of an engine failure while hovering.

Experiments in the Soviet Union also began with a flying bed frame, called a Turboljot, inspired by the British model.

1960s

By 1960 at the latest, it was clear to the military that Soviet nuclear weapons attacks could paralyze NATO airfields within a short time. A remedy was seen in the development of combat and transport aircraft with V / STOL capabilities. NATO defined three aircraft types for the relevant tenders, for which the tenders NBMR-3, NBMR-4 and NBMR-22 were published. By the end of 1961, the companies should have submitted corresponding offers.

Most of the manufacturers who applied for the contract and submitted dozens of suggestions took up the stipulations that a whiz would best meet the requirements. The winners of the tender for a supersonic fighter (NBMR-3a) were the Dassault Mirage IIIV and the Hawker P.1154 . The VFW VAK 191B was declared the winner of the competition for a subsonic fighter-bomber (NBMR-3b). When tendering for the transporter, no acceptable proposal could be found at the first attempt, so that the requirements had to be relaxed somewhat in a new NBMR-22 tender in November 1962. No direct winner was presented this time either , but subsequently the Dornier Do 31 and Fiat G.222 were built and tested as prototypes. The projects were finally abandoned because the NATO leadership failed to convince the government officials of the usefulness of the projects. In particular, the USAF's lack of interest in the V / STOL technology contributed to the abandonment of the project. However, Germany was able to successively produce the EWR VJ 101 (1963), the Dornier Do 31 (1967) and the VFW-Fokker VAK 191 B (1970) and thus acquire a great deal of know-how.

1970s and after

In the early 1970s, many projects were discontinued or canceled and the number of newly initiated projects fell significantly. Only in military use, the Harrier II and the V-22, have two types prevailed. Since the Harrier II is planned to only be used by the US Marines until the beginning of the 2020s, the F-35B will then be the only jet-propelled VTOL aircraft in military use.

Tilt wing technology made a certain breakthrough after the V-22 had proven itself in military use. The AgustaWestland AW609 , which has been in trials for many years, is derived from this . New projects in line with this structural design are the Bell-Boeing Quad TiltRotor and, in the 2010s, unmanned aerial vehicles , where, in addition to a large number of multicopters, convertible aircraft were also preferred. Examples are the Bell Eagle Eye and the Bell V-247 Vigilant.

Chronological list of first flights

The list includes all VTOL aircraft actually flown to date:

Convertible aircraft

Other VTOL aircraft

literature

  • Roy Braybrook: V / STOL - Reflections 40 years on . In: AIR International October 1999, pp. 235–240
  • Hugh W. Cowin: X-Planes - Research Aircraft 1891-1970 (Aviation Pioneers 1) , Osprey Aviation 1999, ISBN 1 85532 876 3
  • Bill Gunston: The development of Jet and Turbine Aero Engines , Patrick Stephens, 1995, 4th edition 2006, 4th reprint 2013, ISBN 978-1-85260-618-3 , pp. 160 ff.
  • Bill Gunston: Harrier - Modern Fighting Aircraft Volume 5 . Arco Publishing, New York, 1984, ISBN 0-668-06069-7
  • Derek Harvey: perpendicular to the future . In: Flug Revue August 1958, pp. 9–11
  • Tim McLelland (Ed.): Hawker Harrier - Warfare with vertical velocity , Airplane Icons No. 18, Key Publishing, 2015, ISBN 978-1-909786-17-0 .
  • Otto E. Pabst: Short takeoff and whiz kid - Die deutsche Luftfahrt Vol. 6 , Bernard & Graefe Koblenz, 1984, ISBN 3-7637-5277-3 , p. 159 ff.
  • The whiz kid . In: Aircraft - The new encyclopedia of aviation, issue 191, pp. 5340–5345
  • The 'flat starters' - The ups and downs of the high-flyers part 2 . In: Airplane - The new collection, issue 5, pp. 134-139
  • The Harrier takes off - The ups and downs of the whiz part 3 . In: Airplane - The new collection, issue 6, pp. 158–165

Web links

Individual evidence

  1. ↑ The Aero of August 24, 1909
  2. ↑ a b AIR Enthusiast No. 54 Summer 1994, p. 14
  3. ↑ Mention of the letter from C Edgar Simpson
  4. ^ Cowin, p. 84
  5. ↑ Photo of the Ryan test facility with a J33 engine on p. 154 ( Memento from October 23, 2016 in the Internet Archive ) (accessed December 12, 2015)
  6. ^ Bill Gunston: Vertijet . In: Airplane Monthly May 1981, p. 229
  7. ↑ Bill Gunston: `` US Navy prop-hangers ''. In: Airplane Monthly, October 1974, p. 891
  8. ^ Roy Allen: Stranger than Fiction - Vertical Flight. In: Airplane Monthly, August 2004, pp. 32–36
  9. ^ Flight dated January 3, 1958
  10. ↑ photo of Turbolyet in Roy Allen, P. 34
  11. ↑ Bell unveils V-247 Vigilant unmanned tiltrotor (accessed October 22, 2016)